1. Field of the Invention
This invention relates generally to the field of disc drive storage devices, and more particularly, but not by way of limitation, to a laminated base deck design for a disc drive.
2. Discussion
Disc drives are commonly used in workstations, personal computers, portables and other computer systems to store large amounts of data in a form that can be made readily available to a user. In general, a disc drive comprises one or more magnetic discs that are rotated by a spindle motor at a constant high speed. The surface of each disc is divided into a series of data tracks which are spaced radially from one another across a band having an inner diameter and an outer diameter. The data tracks extend generally circumferentially around the discs and store data in the form of magnetic flux transitions within the radial extent of the tracks on the disc surfaces. Typically, each data track is divided into a number of data sectors that store fixed sized data blocks.
A head includes an interactive element such as a magnetic transducer which senses the magnetic transitions on a selected data track to read the data stored on the track, or to transmit an electrical signal that induces magnetic transitions on the selected data track to write data to the track. The head includes a read/write gap that positions the active elements of the head at a position suitable for interaction with the magnetic transitions on the data tracks of a disc as the disc rotates.
As is known in the art, each head is mounted to a rotary actuator arm and is selectively positionable by the actuator arm over a preselected data track of the disc to either read data from or write data to the preselected data track. The head includes a slider assembly having an air bearing surface that causes the head to fly over the data tracks of the disc surface due to fluid air currents caused by rotation of the disc.
Typically, several discs are stacked on top of each other and the surfaces of the stacked discs are accessed by the heads mounted on a complementary stack of actuator arms which compose an actuator assembly, or "E-block". The E-block generally includes head wires which conduct electrical signals from the heads to a flex circuit, which in turn conducts the electrical signals to a printed circuit board (PCB) mounted to a disc drive base deck.
As will be recognized, the general trend in the industry is to provide disc drives with ever decreasing form factors and ever increasing storage capacities. Along with increases in spindle motor rotation speeds, areal density of recorded data and faster data access times by disc drive actuator assemblies, customer expectations further include continued reductions in the level of acoustic emissions generated by modern disc drives.
Acoustic noise from a drive is typically generated from resonant vibrations induced in the disc drive top cover and base deck by the operation of the spindle motor and the actuator assembly. A variety of methodologies have been employed to reduce acoustic emissions from disc drives; see for example U.S. Pat. No. 5,475,545 entitled METHOD FOR REDUCING NOISE DURING SEEKS IN A HARD DISC DRIVE issued Dec. 12, 1995 to Hampshire et al., which discloses shaping the velocity profile of an actuator assembly during the acceleration phase of a seek to reduce acoustic noise generated by the seek. Additionally, see co-pending U.S. patent application Ser. No. 08/671,704 entitled LOW SWAY SPACE CHASSIS FOR A DISC DRIVE which discloses the use of an external chassis and vibro-acoustic isolator to reduce acoustic emissions from the drive. Both of these references are assigned to the assignee of the present invention and are incorporated by reference.
A disc drive base deck is typically designed to provide the necessary structural integrity to support the mounting of internal disc drive components as well as to support attachment of the disc drive to a user environment (such as a disc drive bay in a PC). Typically, modern disc drives have base decks which are formed from a casting process using a suitable alloy material and undergo secondary machining operations as required to provide the requisite critical surfaces for proper alignment of the disc drive components. While structurally solid, such cast base decks have been found to be susceptible to high frequency vibrations, resulting in the generation of undesirable acoustic noise during operation of the drive.
There is a need, therefore, for an improved disc drive base deck design which provides the necessary structural integrity to facilitate the mounting and support of internal disc drive components as well as the mounting of the disc drive to a user environment, while at the same time having a reduced susceptibility to high frequency vibrations.